paul wrote:
wrote in message
oups.com...
paul wrote:

I am trying to mix the right quantities of sand, cement and lime to
produce
a 5:1:1 mix.

I'm wondering what youre using 1:1:5 for though, its not a mix I know
of any application for.

The mix I'm using is for a Bulwell stone wall which is also a retaining
wall, i.e has earth behind it all the way to the top of the wall which is
approx 2.5m high. It was recommended by a builder I had round, having said
that the next guy I had round recommended a lime:sharp sand mix without
cement.
Paul

This is a soft stone, a limestone, so should be done in lime mortar
rather than cement. Cement will work, but when it finally comes apart
it pulls the edges and corners off the stone with it, which does not
look good. Lime also has the advantage of being able to accomodate
limited movement, unlike cement.

The standard lime mortar is 3:1, this is 3 parts sand to one lime
putty. The putty is made by mixing bagged hydrated lime with water to
make a paste, and storing it airtight for a few weeks. Cement and lime
mortar is not lime mortar, or anything like it.

I know someone who uses bagged hydrated lime, mixes with sand, adds
water and uses it without storing first, and says he gets good results.
Ive not tried that.

The downside of lime is its slow setting. You dont want to build 8' in
a day, must let the bottom section set first. Also, just like cement,
dont use a bag of lime thats sat around forever. Cement wont mix in the
first place, old lime will, but it wont set. IOW if your lime is old,
test a bit sets ok before use. Unsetting lime is a rare problem.

Finally with lime you can make it more decorative by adding crushed
black stone or coal to the mix, white with black flecks.


NT